我有一个typescript的例子，可以帮助一些新的typescript。

const hyperlinks: string [] = await page.evaluate((url: string, regex: RegExp, querySelect: string) => {
.........
}, url, regex, querySelect);

你必须像这样将变量作为参数传递给pageFunction:

const links = await page.evaluate((evalVar) => {

  console.log(evalVar); // 2. should be defined now
  …

}, evalVar); // 1. pass variable as an argument

你可以通过向page.evaluate()传递更多参数来传入多个变量:

await page.evaluate((a, b c) => { console.log(a, b, c) }, a, b, c)

参数必须可以序列化为JSON或浏览器内对象的JSHandles: https://pptr.dev/#?show=api-pageevaluatepagefunction-args

对于传递函数，有两种方法。

// 1. Defined in evaluationContext
await page.evaluate(() => {
  window.yourFunc = function() {...};
});
const links = await page.evaluate(() => {
  const func = window.yourFunc;
  func();
});


// 2. Transform function to serializable(string). (Function can not be serialized)
const yourFunc = function() {...};
const obj = {
  func: yourFunc.toString()
};
const otherObj = {
  foo: 'bar'
};
const links = await page.evaluate((obj, aObj) => {
   const funStr = obj.func;
   const func = new Function(`return ${funStr}.apply(null, arguments)`)
   func();

   const foo = aObj.foo; // bar, for object
   window.foo = foo;
   debugger;
}, obj, otherObj);

您可以在test的启动选项中添加devtools: true

我鼓励您坚持使用这种样式，因为它更方便、更易读。

let name = 'jack';
let age  = 33;
let location = 'Berlin/Germany';

await page.evaluate(({name, age, location}) => {

    console.log(name);
    console.log(age);
    console.log(location);

},{name, age, location});

与上面@wolf的答案略有不同。使代码在不同上下文之间更容易重用。

// util functions
export const pipe = (...fns) => initialVal => fns.reduce((acc, fn) => fn(acc), initialVal)
export const pluck = key => obj => obj[key] || null
export const map = fn => item => fn(item)
// these variables will be cast to string, look below at fn.toString()

const updatedAt = await page.evaluate(
  ([selector, util]) => {
    let { pipe, map, pluck } = util
    pipe = new Function(`return ${pipe}`)()
    map = new Function(`return ${map}`)()
    pluck = new Function(`return ${pluck}`)()

    return pipe(
      s => document.querySelector(s),
      pluck('textContent'),
      map(text => text.trim()),
      map(date => Date.parse(date)),
      map(timeStamp => Promise.resolve(timeStamp))
    )(selector)
  },
  [
    '#table-announcements tbody td:nth-child(2) .d-none',
    { pipe: pipe.toString(), map: map.toString(), pluck: pluck.toString() },
  ]
)

也不是功能内部管道不能使用这样的东西

// incorrect, which is i don't know why
pipe(document.querySelector) 

// should be 
pipe(s => document.querySelector(s))

我有一个typescript的例子，可以帮助一些新的typescript。

const hyperlinks: string [] = await page.evaluate((url: string, regex: RegExp, querySelect: string) => {
.........
}, url, regex, querySelect);